Heretofore, there have been various known image recording apparatus for recording a desired image represented by image data on an image recording surface.
For example, various exposure apparatus incorporating a spatial light modulator comprising a digital micromirror device (DMD) or the like for modulating a light beam based on the image data have been proposed.
A DMD comprises a memory array (SRAM array) disposed on a semiconductor substrate of silicon or the like and micromirrors disposed two-dimensionally on the memory array. The micromirrors are tilted by controlling electrostatic forces of charges that are accumulated in the memory array, changing the angles of the reflecting surfaces of the micromirrors for thereby forming image recording dots at desired positions on an image recording surface to form an image thereon.
There has been proposed an exposure apparatus which employs a DMD for forming a desired image on an exposure surface by relatively moving the DMD in a predetermined scanning direction with respect to the exposure surface, inputting frame data made up of a plurality of image recording dot forming element data corresponding to a micromirror group, to the memory array of the DMD depending on the movement of the DMD in the scanning direction, and forming a group of image recording dots corresponding to the micromirror groups of the DMD chronologically on the exposure surface (Patent Document 1).
There has also been proposed an exposure apparatus having a DMD inclined a certain angle with respect to the scanning direction to perform the above exposure for thereby increasing the resolution of an image that is formed on the exposure surface.
For performing the exposure using such an exposure apparatus, it is necessary to input frame data to the DMD depending on the relative movement of the DMD in the scanning direction. Therefore, it is necessary to generate a plurality of frame data corresponding to the position of the DMD with respect to the exposure surface prior to the exposure.
A conventional process of generating frame data to form a numeral “2” on an exposure surface as shown in FIGS. 16A through 16E, 17A through 17E, and 18A through 18E will be described below. In FIGS. 16A through 18E, outlined encircled numbers 1 through 8 schematically represent eight micromirrors that make up one DMD.
Frames 1 through 15 shown in the lower ends of FIGS. 16A through 18E schematically represent frame data that are input to the DMD when the DMD is present in the illustrated positions.
Heretofore, for example, image data made up of pixel data corresponding to the respective pixels shown in FIGS. 16A through 18E are temporarily stored in a memory such as a DRAM or the like, and then the pixel data corresponding to the micromirrors represented by the encircled numbers 1 through 8 of the DMD are successively read out from the memory at the respective positions of the DMD shown in FIGS. 16A through 18E, thereby generating frame data made up of image recording dot data.
In FIGS. 16A through 18E, the pixel data represented by blank squares and hatched squares indicate turn-off data “0” for the micromirrors of the DMD, and the pixel data represented by solid squares indicate turn-on data “1” for the micromirrors of the DMD. A range indicated by the hatched squares represents a substantial range of an image recorded on the image recording surface, and has pixel data represented by “0” which are the same as blank squares.
Patent Document 1: Japanese Laid-Open Patent Publication No. 2004-056100